Positron emission tomography works by measuring the spatial distribution of a specific molecular imaging probe, a so-called PET-tracer, in the body of the patient. The tracer is injected in trace amounts into the patient and has the ability to specifically bind to tissue or be enriched in certain areas because of their specific involvement in biological processes. PET-tracers are used in cancer diagnosis and therapy control.
Typically, tracer production includes a first step of synthesizing a tracer, followed by a purification step via high-pressure liquid chromatography (HPLC), followed lastly by a dispensing step where either singe doses of the tracer are dispensed for injection, or a bulk dose for still further dispensement is conducted.
With the development of automated synthesis systems, such as FASTLab®, sold by GE Healthcare, a division of General Electric Company (Liege, BE), tracer synthesis is provided by a disposable cassette operated by a control system (called the synthesizer). The cassette includes the pump, conduits, valves, reagents, reaction chamber(s), filters et al., and is connected to a source of radioactive isotope. Under operation by the synthesizer, the cassette draws the isotope and processes the isotope so as to attach it to a tracer molecule. After the synthesis process, the labeled compound is dispensed, again under direction of the synthesizer, from the cassette for transport to an HPLC system for further purification. After undergoing HPLC, the purified tracer is delivered to a dispense system.
The synthesizer, cassette, HPLC system, and dispense system are located in a shielded hot cell. As the space available in a given hot cell is fixed, the more equipment required to synthesize labeled tracer compounds will affect the free space in the hot cell. Given that systems such as FASTLab can synthesize different tracers, multiple HPLC or dispense systems are needed to make production runs of subsequent tracers. Given the space limitations in the hot cells and the risk of exposure to residual radioactivity, as well as the need for GMP compliance, switching to these alternate HPLC systems can be time consuming, reducing throughput of multiple PET tracers.
Delivery of multiple 18F radiotracers from the radiosynthesis platform can be realised if used in conjunction with a GMP compliant multi-compound radioHPLC system. However, no suitable HPLC device currently exists.
There is therefore a need in the art for an HPLC system which can accommodate multiple tracers without requiring extensive operator intervention to connect to a synthesis device.